To fix this, search in member.php for
$user_homepage = (isset($user_row['user_homepage'])) ? format_url($user_row['user_homepage']) : REPLACE_EMPTY;
and replace it with
$user_homepage = (isset($user_row['user_homepage'])) ? format_text(format_url($user_row['user_homepage']), 2) : REPLACE_EMPTY;